AMBULATORY BLOOD PRESSURE MONITORING IN CKD

Dr. D. S. OokalkarMD DNB Nephrology

Outline

Problem of CKD Problem of HTN in CKD Problem of measurement of blood

pressure Solution – Ambulatory BP monitoring How it is done How the report is interpreted Is it worth the cost

Problem of CKD

Prevalence 3% of the US adult population have

an elevated serum creatinine level and out of that 70% are hypertensive

Hypertension is reciprocally related to GFR

BP control rates are low in CKD

Kidney disease India

The age-adjusted incidence rate of ESRD is 229 per million population (pmp), and >100,000 new patients enter renal replacement programs annually.

{ SEEK study researched 6120 Indian subjects from 13 academic and private medical centers all over India.}

Singh et al. BMC Nephrology 2013, 14:114

The most common risk factors and other characteristics among the subjects diagnosed with CKD were hypertension (64.5%), anemia (40.7%) and diabetes (31.6%

Hypertension- The most common risk factor for Kidney disease --SEEK study India

Risk factors associated with the presence of hypertension in CKD1. Reduced GFR2. Higher BMI3. African-American race4. Increasing age5. Male gender6. Diabetes7. Hypertriglyceridemia8. Proteinuria

PGC

AA EA

How does blood pressure relate to progression of CKD?

BP

In a sick kidney, increased glomerular capillary pressure (GLOMERULAR HYPERTENSION) causes progression of the CKD (increased fibrosis)

Hypertension in different causes of CKD Diabetic Nephropathy – 42.9% Chronic Glomerulonephritis – 25.6% Nephrosclerosis – 9.4% Parenchymal Kidney Disease – 2.4%

Hypertension caused by CKD if:1. Abnormal findings have been obtained

on urinalysis

2. Renal dysfunction has appeared before Hypertension

3. Presence of Hypertension or Proteinuria/renal dysfunction (superimposed pre-eclampsia) from an early period of pregnancy

4. Hypertension is mild relative to abnormal urinary findings of kidney damage

5. Few hypertensive cardiovascular complications concurrent with the kidney disorders

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Hypertension and renal function

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The most common cause of death among ESRD patients is CVD

Fig 5. Causes of death among period prevalent patients 1997–1999, treated with hemodialysis, peritoneal dialysis, or kidney transplantation. Data are from the USRDS 2001 Annual Data Report (www.usrds.org). Abbreviations: MI, myocardial infarction; HD, heart disease.

Problem of HTN in CKD – increased CVD Risk

The BP relationship to risk of CVD is continuous, consistent, and independent of other risk factors.

Each increment of 20/10 mmHg doubles the risk of CVD across the entire BP range starting from 115/75 mmHg.

Problem of HTN in CKD-CKD and CVD

• CKD is associated with an increased risk of CVD• Cardiovascular complications cause 40-50% of deaths in those with CKD• Risk of CVD mortality is 50- 500 times higher than that of age-matched individuals in general population• Patients with CKD are the “highest risk group” for CVD events.

50 yo male with HT and azotemia (sCr 2.0 mg/dL)

Delay dialysis byAt least 5 yrs

Summary of adequate BP control and CKD

SOLUTION

Benefits of Lowering BP

Average Percent Reduction

Stroke incidence 35–40%

Myocardial infarction 20–25%

Heart failure 50%

Benefits of Lowering BP

In stage 1 HTN and additional CVD risk factors, achieving a sustained 12 mmHg reduction in SBP over 10 years will

prevent 1 death for every 11 patients treated.

BP Measurement

BP Measurement Techniques - • In-office• Ambulatory BP Monitoring• Home BP measurement

BP MEASUREMENT

Office BP Measurement is the standard of Care

Office BP Measurements has limitations like1. Cannot Identify White Coat Hypertension2. Cannot identify Masked Hypertension3. Cannot identify Nocturnal Hypertension4. BP Medication cannot be prescribed to get good control on blood pressure.

Implication of White Coat Hypertension and Masked Hypertension on CKD

Masked hypertension increases the chances of ESRD compared with those with truly normal BP, and those with white-coat hypertension had lower risk for ESRD compared with patients with persistent hypertension.

ABPM Ambulatory BP monitoring can more

precisely characterize changes in BP throughout daily activities

ABPM has been found to be superior to Clinic BP monitoring in predicting cardiovascular morbidity and mortality

ABPM have widespread use in evaluation for hypertension and risk of end-organ damage in adults

Ambulatory Blood Pressure Monitoring should be done in patients with CKD

ABPM

Most studies have shown that end-organ damages associated with hypertension, including left ventricular (LV) hypertrophy, proteinuria, serum creatinine, atherosclerotic plaque, narrowing of the retinal arteries, and impaired arterial distensibility and compliance, are more strongly correlated with ABPM than with clinic BP measurements

ABPM

In treated or untreated patients with hypertension, ABP is a significantly better predictor of cardiovascular (CV) and cerebrovascular events than clinic BP measurements

Indications of ABPM

Evaluating the effectiveness of drug therapy for hypertension

Confirming the diagnosis of hypertension To determine whether true Hypertension of WCH

persists To evaluate the presence of Masked Hypertension

when there is clinical suspicion of Hypertension but normal casual measurements

Assessment of BP variability Assessment of dipping status Suspicion of Nocturnal Hypertension Marked discordance between office BP and

home BP

How Ambulatory Blood Pressure is monitored? An oscillometric or auscultatory technique can be

used Appropriate cuff sizes must be available for device

selected Devices should be programmed to record BP every

20 – 30 minutes during waking hours and every 30 – 60 minutes during sleep hours

After application, BP measured with the device should be compared with resting, clinic BP using the same technique as used by the ambulatory device.

Patients should be instructed to record antihypertensive medication administration, activity, sleep and wake times in a diary.

Cuff

Connecting Tube

ABP Device

Figure 1. Definition of morning surge in BP.

Standard patterns in ABPM

Common to all plots: vertical axes show

blood pressures; horizontal axes shot 24-hour clock times;

horizontal bands indicate normal values for 24-hour SBP and DBP;

shaded vertical areas indicate night-time.

(A. This ABPM suggests normal 24-hour SBP and DBP (128/78 mm Hg daytime, 110/62 night-time),....

White Coat Hypertension

(B) White-coat hypertension. 

This ABPM suggest WCH (175/95 mm Hg) with otherwise normal 24-hour SBP and DBP (133/71 mm Hg daytime, 119/59 mm Hg night-time)

(C) White-coat effect. This ABPM suggests mild daytime systolic hypertension (149 mm Hg), borderline daytime diastolic hypertension (87 mm Hg), borderline night-time systolic hypertension (121 mm Hg), and normal night-time DBPs (67 mm Hg) with white-coat effect (187/104 mm Hg).

White Coat Hypertension

Systolic and diastolic hypertension

(D) Systolic and diastolic hypertension. This ABPM suggests mild daytime systolic and diastolic hypertension (147/93 mm Hg), but normal night-time SBP and DBP (111/66 mm Hg)

ISH

(E)Isolated systolic hypertension. This ABPM suggests severe 24-hour isolated systolic hypertension (176/68 mm Hg daytime, 169/70 mm Hg night-time)

Dippers and non-dippers

Blood pressure will fall at night in normotensive individuals. People who undergo this normal physiological change are described as 'dippers'.[11] 

In 'non-dippers' the blood pressure remains high, ie less than 10% lower than daytime average. There is also the phenomenon of 'reverse dippers' whose blood pressure actually rises at night. Both these conditions have also been reported to be associated with a poor outcome.[11] 

TYPES OF DIPPING

Dipper- 10- 20%

Nondipper- 0- 10%

Extreme Dipper- more than 20%

Reverse dipper- Night BP is higher than day time

SBP

Non Dipping

Nocturnal blood pressure dips <10%

• The non-dippers in treated hypertensive patients were

associated with adverse cardiac remodeling and early

LV dysfunction.• International Journal of Cardiology 112 (2006) 171–177

• Non-dippers often have ischemia at night. And also possess

autonomic abnormalities• M. Kurpesa et al. / International Journal of Cardiology 83 (2002) 133 –142

Dipping and CKD

Hypertension often presents as a different phenotype in CKD, with a greater likelihood of salt sensitivity, a higher frequency of hypertensive emergencies, and a different 24-hr profile of blood pressure (such as the lack of a nocturnal dip in blood pressure).

Kidney International (2010) 77, 753 – 755.

Hypertensive dipper

(F) Hypertensive dipper. This ABPM suggests severe daytime systolic hypertension (181 mm Hg), moderate daytime diastolic hypertension (117 mm Hg) and normal night-time SBP and DBP (111/68 mm Hg)

Hypertensive non-dipper

(G) Hypertensive nondipper. This ABPM suggest severe 24-hour systolic and diastolic hypertensive (210/134 mm Hg daytime, 205/130 mm Hg night-time).

Interpretation of ABPM

Pulse pressure

Pulse pressure is the pressure that is felt when

feeling the pulse.

It is the systolic pressure minus the diastolic

pressure i.e. 40 – 45 mmHg

Extremely low, i.e. 25 mmHg or less

low stroke volume as in Congestive Heart Failure

Greater than 100 mmHg - Stiffness of the major

arteries,  leak in the aortic valve

10 mm Hg increase in pulse pressure increases the

risk of major cardiovascular complications and

mortality by nearly 20% and/or shock

45

Recommended standards for normal and abnormal pressures during ABPM.

Ambulatory BP and CKD

….ambulatory BPs seem to be better correlates of left-ventricular hypertrophy and mortality in hemodialysis patients compared with pre/post-dialysis BP.

Blood Press Monit. 2009 Feb;14(1):2-11

Ambulatory BP and CKD

The strength of the relationship between proteinuria and systolic BP was in the order ambulatory > home > standardized clinic > routine clinic BP measurement……

Nocturnal dipping was associated with higher estimated GFR, higher serum albumin, younger age, and less proteinuria.

Proteinuria is the most important correlate of systolic BP in older men, the strongest relationship of which was with ambulatory and home systolic BP.

Hypertension. 2005 Sep;46(3):514-20. 

Ambulatory BP and CKD

Systolic ambulatory BP and nondipping are independent predictors for ESRD after adjusting for clinic BP.

Kidney Int. 2006 Apr;69(7):1175-80

Ambulatory BP and CKD

The non-dipping phenomenon is closely related to a high incidence of CV diseases, a poor long-term survival and profound autonomic dysfunction.

ABPM is useful in predicting long-term CV prognosis in HD patients.

Nephrol Dial Transplant. 2003 Mar;18(3):563-9.

Ambulatory BP and CKD

lack of or reduction of nocturnal BP fall (non-dipping pattern) ..

an increase of target-organ damage a greater frequency of cardiovascular

events and higher cardiovascular mortality in non-dippers ..

ABPM could be a useful method to evaluate the initial global cardiovascular risk in patients with hypertension.

Recenti Prog Med. 2007 Jul-Aug;98(7-8):401-6.

ABPM in CKD

 Patients with CKD have a high prevalence of a nondipping pattern (67%)

prevalence of nondipping patterns is higher at lower GFR. Fifty-three percent of CKD patients with serum creatinine of <4.5 mg/dL (<400 µmol/L) had nondipping pattern progressing to 75% with creatinine of >6.8 mg/dL (>600 µmol/L)

KDOQI Clinical Practice Guidelines on Hypertension and Antihypertensive Agents in Chronic Kidney Disease APPENDIX 3

ABPM results have a close correlation with end-organ damage, including progression of kidney disease .

The presence of a nondipping pattern or nocturnal hypertension in a patient with CKD places an already high-risk patient into an even higher-risk group. This knowledge may be helpful in suggesting an even more aggressive therapeutic regimen.

KDOQI Clinical Practice Guidelines on Hypertension and Antihypertensive Agents in Chronic Kidney Disease APPENDIX 3

ABPM in CKD